I am quite new to ruby so bear with me, I have two arrays and we are meant to find the number which is missing.
The starting array sequence is [1,2,3,4,5,6,7,8,9] The mi
You are passing in mixed as an argument and then are using it as mixed_arr.inject..., seems to work fine making those consistent.
Also, since you are passing in the arr and mixed you don't need them to be set in the method, you can call it as
find_deleted_number([1,2,3,4,5,6,7,8,9], [3,2,4,6,7,8,1,9])
and then remove
arr = [1,2,3,4,5,6,7,8,9]
mixed = [3,2,4,6,7,8,1,9]
from the beginning of your method.